161181191 has 4 divisors (see below), whose sum is σ = 161206584. Its totient is φ = 161155800.

The previous prime is 161181187. The next prime is 161181193. The reversal of 161181191 is 191181161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 161181191 - 2² = 161181187 is a prime.

161181191 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161181193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6221 + ... + 19001.

It is an arithmetic number, because the mean of its divisors is an integer number (40301646).

Almost surely, 2^161181191 is an apocalyptic number.

161181191 is a deficient number, since it is larger than the sum of its proper divisors (25393).

161181191 is a wasteful number, since it uses less digits than its factorization.

161181191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25392.

The product of its digits is 432, while the sum is 29.

The square root of 161181191 is about 12695.7154583741. The cubic root of 161181191 is about 544.2161849374.

The spelling of 161181191 in words is "one hundred sixty-one million, one hundred eighty-one thousand, one hundred ninety-one".